Process for resolving petroleum emulsions



o appearance.

2 Patented Feb. 11, 194i UNITED STATES PATENT OFFICE raocn ss FORRESOLVING PETROLEUM EMULSIONS No Drawing. Application February 20, 1939,

, Serial No. 257,332

4 Claims.

This invention relates primarily to the treatment of emulsions ofmineral oil and water, such as petroleum emulsions, for the purpose ofseparating the oil from the water, and has for its main object toprovide a novel process for resolving or breaking petroleum emulsions ofthe water-in-oil type.

Petroleum sulfonic acids are produced from a wide variety of petroleumdistillates or petrole- -l um fractions, and in some instances, they areproduced from the crude petroleum itself. When produced from crudepetroleum itself, it is customary to use crude oil of the naphthenetype, crude oil of the parafiin type, crude oil of the as- 15 phaltictype, and mixtures of said three different types of crude oil.

The art of refining petroleum crude or various fractions, usingsulfuricacid of various strengths, as well as monohydrate and fuming acid, is awell 20 known procedure. In such conventional refining procedure,petroleum sulfonic acids have been produced as by-products. Forinstance, in removing the olefinic components, it has been commonpractice to use sulfuric acid so as to poly- 25 merize the olefines orconvert theminto sulfonic acids which are subsequently removed.Likewise, inthe production of white oil or highly refined lubricatingoils, it has been customary to treat with fuming sulfuric acid, so as toeliminate cer- 30 tain undesirable components.

In recent years, certain mineral oil fractions have been treated withsulfuric acid, with the primary object of producing petroleum sulfonicacids, and in such procedure the petroleum sula5 fonic acids representedthe primary objects of reaction, rather than concomitant by-products.

Petroleum sulfonic acid, regardless of whether derived as the principalproduct of reaction or as a by-product, can be divided into two general40 products, to wit, green acid or acids, and mahogany acid or. acids.The green acids are characterized by being water-soluble or dispersible.In other words,'they form either true solutions or sols. For purpose ofconvenience, they will be 45 herein referred to as water-soluble,without any effort to indicate. whether the solution is molecular orcolloidal in nature. The greenacids, as indicated by their name,frequently give an aqueous solution having a dark green or grey-greenThey, enerally appear as a component of the acid draw-0H, and do notremain behind dissolved in the oil fraction which has been subjected tosulfuric acid treatment. The green acids are not soluble in oil, evenwhen sub- 5 stantially anhydro and certainly are not soluble in oil whenthey contain as much as 15% of water. Similarly, their salts obtained byneutralizing the green acids with a strong solution of caustic soda,caustic potash, or ammonia, are not oil soluble. For convenience ofclassifica- 5 tion, the ammonium salt will be considered as an alkalisalt. I

y In contradistinction to the hydrophile green acids, there occurs, asin the manufacture of medicinal white oil, the oil soluble type, or themahogany acids. These mahogany acids are characterized by being solublein oil, especially when anhydrous, and being soluble in oil, even ifthey contain some dissolved water. Some of the mahogany acids also showlimited hydrophilic properties to the extent that either some watereanbe dissolved in the acids, or they, in turn, may

dissolve to some extent in water. In some instances their salts, such asthe sodium, ammonium, or potassium salt, will dissolve in water to givea colloidal sol. However, regardless of the presence of any hydrophilicproperties whatsoever, they always have a characteristic hydrophobeproperty, as indicated by the fact that the substantially anhydrousform, for instance, their alkali salts containing 55-12% water, willdissolve in oil. This clearly distinguishes them from the green acidspreviously referred to, because the green acids in similar formcontaining the same amount'of water, for example, will not dissolve inoil. The green acids as such are essentially hydrophilic andnon-hydrophobic in character.

The utility of the mahogany acids in various arts has been enhanced byincreasing their water solubility; for instance, converting the mahoganyacids into hydroxy alkylamine salts. 0n the other hand, so far as I amaware, no valuable product of commerce has resulted from decreasingthewater solubility of the mahogany acids 40 by the addition of some oilsoluble basic amine, such as, for example, triamylamine. Thetria'mylamine salts of mahogany acids,.for example, are completelydevoid of any solubility in water which the alkali salts may haveexhibited, and show, as would be expected, an increased solubility inhydrophobe solvents. 7

Green acids are hydrophile in character, as previously stated. Theirhydrophile character has been increased by neutralization with materials'such as triethanolamine and the like. Such'green acid salts havingenhanced water solubility, as compared with the ordinary alkali salts,have found applica on in certain arts.

I have found that if n acids, that is, the

oil-insoluble type, are neutralized with an alkylamine of the kindhereinafter described so as to produce a water-insoluble product, theresulting material, even though it does not exhibit any marked oilsolubility, especially when it contains 5-10% of water, still haspronounced value as a demulsifier for oil field emulsions, either whenused alone, or when used in conjunction with other known demulsifyingagents. I employ alkylamines of the kind which contain at least onebutyl radical, and contain no other radical in which there are more thanfour carbon atoms present. Attention is directed to my co-pendingapplication for patent, Serial No. 193,063, filed February 28, 1938 nowPatent 2,153,745. I have also found that sometimes such an amine salt ofgreen acids will mix in with a hydrophobe material and a hydrophilematerial, so as to produce a homogeneous mixture. The efiectiveness ofthe above described material or composition of matter as a demulsifyingagent for oil field emulsions appears to be related to some factor otherthan its solubility characteristics.

The new composition of matter then which I use as the. demulsifier in myimproved process for resolving petroleum emulsions, is represented bythe described alkylamine salts of hydrophilic non-hydrophobic greenpetroleum acids, as exemplified by the dibutylamine salt. Themanufacture of said new composition of matter involves nothing more orless than neutralizing the selected petroleum sulfonic acid with asuitable amine until neutral to methyl orange indicator, or othersuitable indicator. For purpose of convenience, I prefer that theselected petroleum sulfonic acid contains not over of water. It isunderstood, of course, that the conventional procedure employing doubledecomposition, instead of direct neutralization, can be employed in themanufacture of my new material or composition of matter. For instance,the sodium salt of the selected petroleum sulfonic acid can be dissolvedin alcohol and the amine hydrochloride added so that sodium chloridewill precipitate. After filtering off the precipitated sodium chloride,the, alcohol can be evaporated and the amine salt recovered. If desired,a mixture of amines, instead of a single amine, may be employed.

There are a large number of alkylamines available, which arecharacterized by having present at least one butyl radical and no otherradical having more than four carbon atoms. Suitable examples includemonobutylamine, dibutylamine, tributylamine, ethyldibutylamine,methyldibutylamine, dimethylbutylamine, diethylbutylamine,dibutylethanolamine, etc.

There is no objection to using an alkylamine of the kind described, eventhough a hydroxy alkyl radical is present, provided that neutralizationof the green acids yields a water-insoluble salt. For instance, as hasbeen pointed out, one might employ dibutylethanolamine ordibutylpropanolamine. Similarly, one might employ dibutylbutanolamine,or an amine containing a glyceryl radical, such as dibutylglycerylamine,provided that the salt derived from the green acids was water-insoluble.

It may be well to point out that hydrophile non-hydrophobe petroleumsulfonic acid, or acids of the green acid type vary somewhat; forinstance, the molecular weight v.may vary within the range of 350-500,or thereabouts. Naturally, these petroleum sulfonic acids may carry somepolymerized olefines, free hydrocarbons, or the like, or may even carrya bit of naphthenic acids which represent carboxylated non-sulfonatedpetroleum acids. As previously stated, these materials are well-knowncommercial products, and are available in the open market, either in theform of the acid itself, or in the form of a salt.

In the claims the amine is referred to as basic to indicate that thebasicity is in the neighborhood pf that of ammonia or triethanolamine.In some instances, the basicity may be somewhat greater, or perhapsslightly less. Basicity is insured in amines of the kinddescribed,because they do not have present an aryl radical attached to the aminonitrogen atom. The limitation which prohibits the use of an amine havingmore than four carbon atoms excludes the use of amines having a phenyl,naphthyl or similar aryl radical, which would decrease or destroy thebasicity of the amine. used in the claims, is intended to refer to asubstance that consists either of a single acid or mixtures of acids.

The new process that I have devised for resolving or breaking petroleumemulsions of the water-in-oil type involves subjecting the emulsion tothe action of a demulsifier consisting of the above described newmaterial or composition of matter. Said material is used either alone,or in admixture with another or with other conventional demulsifying'agents, and its method of use is the same as that generally employed inresolving or breaking petroleum emulsions of the water-in-oil type witha chemical demulsifier. Briefly stated, the conventional method of usinga chemical demulsifier to break a petroleum emulsion consists inintroducing the demulsifier into the Well in which the emulsion isproduced; introducing the demulsifier into a conduit through which theemulsion is flowing; or introducing the demulsifier into -a tank inwhich the emulsion is stored. After treatment the emulsion is allowed tostand in a quiescent state, usually in a settling tank, and usually at atemperature varying from atmospheric temperature to about 200 F., so asto permit the water or brine to separate from the oil, it beingpreferable to keep the temperature low enough to prevent thevolatilization of valuable constituents of the oil. The amount ofdemulsifier that may be required to break the emulsion may vary from 1part of demulsifier to 500 parts of emulsion, up

to 1 part of demulsifier to 20,000 or even 30,000

parts of emulsion.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is: a

1. A process for resolving petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action ofa demulsifiercomprising a water-insoluble salt of a basic alkylamine; said aminebeing characterized by the fact that at least one amino hydrogen atomhas been replaced by a butyl radical and that said amine is free fromany radical containing more' than four carbon atoms; said amine saltbeing obtained from water-soluble, non-hydrophobe, petroleum sulfonicacid of the green acid type.

2. A process for resolving petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifiercomprising a water-insoluble salt of The term sulfonic acid,

monobutylamine; said amine salt being obtained from water-soluble,non-hydrophobe, sulfonic acid of the green acid type.

3. A process for resolving petroleum emulsions of the water-in-oii type,characterizedby sub jecting the emulsion to the action of a demulsifiercomprising a water-insoluble salt of dibutylamine; said amine salt beingobtained from watar-soluble, non-hydrophobe, sulfonic acid of the greenacid type.

